Hydraulic apparatus for extracting energy from wave motion are known. Examples of such apparatus are disclosed in published International patent applications for CETO™ technology, PCT/AU2006/001187 and PCT/AU2007/001685 which are incorporated herein by reference.
A prior art hydraulic apparatus for extracting energy from wave motion includes a base which is positioned on the seabed of a body of water. An axial hydraulic pump is mounted on the base such that the pump is able to pivot relative to the base. A piston rod of the pump is coupled to a buoyant actuator by a tether. Wave motion and the positive buoyancy of the buoyant actuator causes it to follow the motion of the water disturbance such that the buoyant actuator is forced upwards exerting force on the tether and expelling fluid via one-way valves under pressure from the pump into a manifold. During passage of the wave trough, the buoyant actuator falls under the weight of the pump piston and the force from pump inlet pressure, priming the pump ready for the next upward thrust of the buoyant actuator.
The apparatus is designed to operate in a closed-loop mode where fluid at high pressure is pumped ashore by the hydraulic pump, energy is extracted as useful work, and the reduced pressure fluid is returned via piping to the offshore hydraulic pump to be re-energised.
An alternative prior art hydraulic apparatus is similar to the aforementioned prior art apparatus except that it includes an array of hydraulic pumps, and an array of buoyant actuators that are each tethered to a respective piston rod of each pump.
Prior art apparatus such as those described above typically need to be specifically tailored to operate in a particular location under the particular conditions associated with the location, including the wave conditions and tidal variations that are associated with the location. This usually involves manufacturing non-standard hardware that is specifically designed for use at the particular location, and also configuring the hardware to operate in a particular way that is suitable for the location.
The need to design and manufacture such non-standard hardware means that it is difficult to streamline the manufacturing process to achieve high volumes of production at lower cost.
It is against this background and the problems and difficulties associated therewith that the present invention has been developed.